ADS BibCode:1977Msngr...8....2TAuthor(s)/Affiliation(s):Thé, P.S.AA(Astronomical Institute of the University of Amsterdam)Abstract:Dr. P. s. Thé from the Astronomical Institute of the University of Amsterdam is a frequent visitor on La Silla, where he often uses the ESO 1-m telescope for measurements of very faint, red (cool) stars. His research programme is intimately connected with one of the greatest enigmas of modern astronomy: there appears to be more mass in the space surrounding the solar system than we actually observe. Whether this "missing mass" is present in the form of black holes, low-luminosity stars or interstellar material, or whether the theoretical considerations that predict the existence of the "missing mass"somehow are wrong, no one knows for sure. But to solve the problem, more accurate observations are needed: Dr. The outlines recent research in this field and informs about his programme:

ADS BibCode:1977Msngr...8....3.Author(s)/Affiliation(s):ESOAA(ESO)Abstract:It is often seen in science that more is learned from abnormal ("pathological") cases than from the normal ones. This is certainly true in astronomy too.

ADS BibCode:1977Msngr...8....3MAuthor(s)/Affiliation(s):Mayor, M.AA(Geneva Observatory)Abstract:The measurement of radial velocities, i.e. the velocity in the direction of the line of sight, is of fundamental importance in stellar as well as in galaxy astronomy. Until the 1960s the only possible method was to obtain a spectrum on a photographie plate and then measure the displacement of the spectral lines. These observations were extremely time-consuming for faint objects. With the advent of image-intensifying devices, the observing time was drastically reduced, but so was-unfortunately-the accuracy of the measurement, due to geometrie distortions in the image tubes. Now, however, the situation has improved very much indeed, as explains Dr. M. Mayor of the Geneva Observatory, who, together with several European colleagues, is building a spectrometer to determine stellar radial velocities by a carrelation method.

ADS BibCode:1977Msngr...8....5HAuthor(s)/Affiliation(s):Havlen, R.; Quintana, H.AA(ESO) AB(NRAO, formerly ESO)Abstract:Dr. R. Havlen (ESO statt astronomer in Chile) and Dr. H. Quintana (former ESO fellow in Geneva, now with NRAO, Charlottesville, Virginia, USA) recently undertook a thorough study of the southern X-ray cluster of galaxies CA 0340- 538. Ever since satellites with sensitive X-ray detectors first showed the presence of strong X-ray sources near the centres of rich clusters of galaxies, astronomers have been asking: why and how? Some even think that high-energy astrophysics has never had as fascinating a subject for study as the central regions of X-ray clusters. Here, as in any other field ofastronomy, observations are ofparamount importance. Drs. Havlen and Quintana introduce the new field and explain their programme:

ADS BibCode:1977Msngr...8....6.Author(s)/Affiliation(s):ESOAA(ESO)Abstract:In the June 1976 issue of THE MESSENGER (No. 5, p. 5), we reported on the joint ESO/Uppsala programme, the aim of which is to establish a catalogue of conspicuous objects on the ESO (B) plates. Since that time, good progress has been made and about 300 fields (or half of lhe ESO (B) Atlas) have now been searched. Approximately 9,000 objects have been listed; just recently, the fourth ESO/Uppsala list was published in the Astronomy & Astrophysics Supplement Series (Holmberg et al., 27, 295).

ADS BibCode:1977Msngr...8....8DAuthor(s)/Affiliation(s): J. Disney, M.AA(ESO)Abstract:A photon carries only four separate pieces of information: a direction, an energy, a polarization and a time of arrival in our detector. Of these four the easiest to measure is the last, and yet accurate timing has been, for reasons good and bad, sadly neglected. Nowadays, with relatively simple equipment, it is possible to do photometry with much higher timing precision than astronomers have generally used before. Nature so often provides surprises for those willing and able to push measurement into a new domain, that on grounds of principle alone fast photometry deserves much more of our atlen-tion.

ADS BibCode:1977Msngr...8...10SAuthor(s)/Affiliation(s):Swings, J.-P.AA(ESO)Abstract:HD 45677 may be considered the prototype for these peculiar emission-line stars that are now called B[e]'s, i.e. Be stars whose spectra exhibit forbidden lines as well as permitted lines of H, Fe II,... HD 45677 has the following coordinates: alpha = 6/126m and delta =-13'. It is therefore ideally located to be observed from La Silla during the summer or early fall in the southern hemisphere. in other words al epochs when the weather is perfect. I should probably mention here that out of the 57 nights that were allocated to me by ESO and by CARSO (ten nights at Las Campanas) between 1972 and 1976, only three could not be used for spectroscopy: that corresponds to a 95 % record!

ADS BibCode:1977Msngr...8...12CAuthor(s)/Affiliation(s):Cesarsky, D.; Falgarone, E.; Lequeux J.AA(Departement de Radioastronomie, Observatoire de Meudon) AB(Departement de Radioastronomie, Observatoire de Meudon) AC(Departement de Radioastronomie, Observatoire de Meudon)Abstract:On the cover of the December 1976 issue of THE MESSENGER was reproduced one of the first photos taken with the new ESO 3.6-m telescope: it represented a dwarf irregular galaxy in the southern constellation Sculptor. This galaxy was named SDIG by Drs. Laustsen, Richter, van der Lans, West and Wilson who reported about its optical properties in Astronomy & Astrophysics 54, p. 639 (January 1977). The Messenger photograph clearly shows resolved blue supergiant stars, which allowed the ESO astronomers to estimate the distance of SDIG at about 3 megaparsecs, or 9 million Light-years.

ADS BibCode:1977Msngr...8...14.Author(s)/Affiliation(s):ESOAA(ESO)Abstract:While this issue of THE MESSENGER goes to press, the Cassegrain adapter is being installed on the ESO 3.6-m telescope. Soon after, the optical tests for the Cassegrain focus will commence, and if all goes well, the first astronomical observations may be made some weeks later.